PM Jacinda Ardern said the four week lockdown allowed health authorities to see where the spread had happened but should have stopped further transmissions. It would be four weeks minimum, she said.
Whanganui Prison is undergoing strict procedures during the lockdown period to maintain physical distancing between prisoners and staff.
All prison sites, including Whanganui, have temporarily suspended private visits to the prison, guided and temporary release of prisoners and release-to-work activities.
There have been no suspected or confirmed cases of Covid-19at Whanganui Prison.
A Department of Corrections spokeswoman said the prisons were running reduced unlock hours in some units to ensure staff and prisoners were able to maintain physical distance while out of their cells.
"For example, in a high-security unit where 20 prisoners may have previously been unlocked in a yard space for 90 minutes, smaller groups of prisoners may now use the yard for a shorter period of time, with enhanced cleaning undertaken between use."
She said in a low-security unit where 60 prisoners would have been unlocked at one time, prisoners could be unlocked in groups of 20.
The spokeswoman said this all varies across the prisoners nationwide due to site and normal operational requirements. These include the need to manage a dynamic range of issues including gang tension and the association of co-offenders.
"At all times, segregated prisoners continue to be provided with minimum entitlements set out in the Corrections Act. They also have regular and ongoing contact with Corrections staff, including our health services staff as required."
National Corrections Commissioner Rachel Leota said other activities such as face-to-face programmes and some industries including textiles and carpentry had been temporarily stopped.
This included face-to-face visits by legal advisers, specified visitors and statutory visitors.
All prisoners will be given a weekly $5 phone card to stay in contact with their friends and family as all visits to the prison have been stopped during lockdown. Photo / File
Leota said the Corrections chief executive, Jeremy Lightfoot, could still approve statutory visits where necessary and there were assurances they could be conducted safely.
"These measures do not change prisoners' access to legal counsel. Visits will still take place by other means, such as over the phone, AVL where available, and postal, courier and email communication in line with our legally privileged correspondence documents processes."
She said prisoners had been supplied with a $5 phone card weekly as well as making it possible for prisoners to receive emails sent to them. They will still receive any approved personal property sent to the site as per usual processes.
To further prevent any potential for virus transmission into the prison, any new prisoners are health screened and kept separate from other prisoners for 14 days.
"If our health screening determines that a newly received prisoner has symptoms or potential symptoms of Covid-19, we take immediate steps to further isolate them as a precaution and to notify the Ministry of Health so all appropriate steps can be undertaken, both at our sites and in the community."
All custodial and health staff working within the prison are now wearing disposable gloves and masks.
